Some exercises are performed without the use of supplemental equipment. For example, a person may perform sit-ups or crunches to strengthen his or her abdominal muscles without the use of supplemental equipment. However, sit-ups and crunches may only work a limited region of the abdominal muscles. As another example, a person may walk, jog, or run without the use of specialized equipment.
Other exercises may be performed with supplemental equipment. The supplemental equipment may be designed to enhance the workout and/or to make the workout more comfortable. One such piece of supplemental equipment is the TRX® suspension training device available from Fitness Anywhere, LLC of San Francisco, Calif. The TRX® device is inelastic and requires the user to suspend his or her body weight, such as by as leaning or hanging from the device. However, these movements may put unwanted pressure on the user's joints and make the user unstable.